A thermoelectric module is a device that exploits the thermoelectric effect exhibited by many materials. FIG. 1 shows a schematic diagram of the operation of a thermoelectric module 100. A thermoelectric module such as module 100 has the property that when current is passed through the module, for example at terminals 101, one side 102 of the module is cooled and the other side 103 is heated. Thermoelectric modules are used in this way in certain consumer devices such as water coolers and the like.
The thermoelectric effect is reversible, such that when the two sides of a thermoelectric module are held at different temperatures, the module can generate electric power. For example, in FIG. 1, rather than driving a current through terminals 101 to heat and cool module sides 102 and 103, the module sides 102 and 103 may be held in a temperature differential, and a voltage will be produced across terminals 101. When used to generate power, a thermoelectric module may be called a thermoelectric generator (TEG). The voltage produced and the amount of power available from the module depend on the temperature differential between the two sides 102 and 103, the materials used to construct the module, the absolute temperature at which the module is operated, the size of the module, and other factors.
This variability of available power makes it difficult to use thermoelectric generation to exploit temperature differentials or gradients that are variable, especially to supply power to a load that has specific requirements for the character of the power it receives.